Self Balancer

I have been ever so slowly building a self balancing robot. I built one a few years ago that did not work to well and ended up using the motors on another machine. This time I decided to 3D print some of the support peices, specifically the battery housing, CPU board mounts, column support brackets, and the motor mounts. The base plate and columns are hardware store Aluminum.

Vererak posted a forum topic called "Parametric robot rover" in which he describes working with Python to develop 3D models. I am a complete novice at 3D printing and for my first stab at modeling I tried openSCAD.

openSCAN is a "C" like language with variables, loops, functions etc.  I had a great number of failures getting started. It will compile with miss-spelt or missing variables and supply default values without warning. Sometimes it will even proceed with missing modules (functions). When it does report an error, the line number is usually useless. There are newer revisions but my Linux dosn't support them.

On the subject of variables, this language has to be the worst I have ever used. Apparently the entire source code is parsed and the last assignment is used, UNLESS, the assignment is inside a module. And then a different set of rules applies.

For the good side, I really like the ability to parametrize just about everything. I quessed at the CPU board witdh and set the span between the upright columns at 60mm. When I built the CPU support bracket I realize that I needed 70mm. One line change, 5 seconds rebuild, and the new model is displayed. I constructed the modues as independent files. That way I can make a top level  file that is the entire robot and other top levels for the printable parts.

I still have to do the motor mounts and will probably do simple mockups of the CPU and MMU boards. Have no idea if it is possible to model the electrical wiring.

There is a feature to export stl files that can be processed by the next step in the 3D print chain. The process is not perfect.

I have most of the remaining mechanical and electrical components. I expect to have a 3D printer in a couple of weeks. Hopefully there will be side by side pictures. Basile has indicated that there is animation feature available.

Current picture has parts to be printed in red.